Forsberg was the artistic director of Almqvist & Wiksell 1942-50 and at Norstedts 1950, where he designed books. Bibeln med bilder av Rembrandt (Bible with pictures by Rembrandt) (1954) is one of Forsberg's great achievements as a designer. The book was one of the first set with Forsberg's own typeface Berling antikva (1951). Forsberg created several typefaces, including Parry (1938), Lunda (1941) and Carolus (1953), as well as logos for a number of Swedish companies, such as Swedish Radio, Volvo, Royal Library and the University of Stockholm and created the image of Stockholm City Arms that the City of Stockholm's use in its graphic identity. Forsberg also published several books: Exlibris, monogram och andra märken (Bookplates, monograms and other markings) (1981) and Mina bokstäver (My letters) (1983), Vandring bland bokstavsformer (Wandering among the letter forms) (1992) and others. On his 75th birthday in 1989 the Forsberg Berling Prize was instituted, awarded to a Swedish graphic artist every year since 1991.
In 1965, he designed a text-only diploma for winners of the Nobel Prize in Physiology or Medicine.